97 siverado a/c problems

[kb99]

Replaced the condenser and manifold on a 1997 chevy silverado and drew a vacuum on the system, when adding freon to the system the first can pushed the pressure up to 70 PSI on the low side and it has stayed there. Any help?

[brcidd]

Is compressor engaging? It should (at 47 psi)... If not, you may have a faulty cycling switch (on silver A/D). It is okay to jumper the wiring harness after disconnecting from the switch. Just don't let low side run below 20 psi for very long.

If compressor is running and you have 70 psi low side, then what do you remember about condenser replacement.....are you sure there is an orifice tube in condenser outlet? Is condenser plumbed correctly? both ends are the same and it can be plumbed backwards....be sure that compressor feeds the top of condenser and that bottom line on condenser (where Orifice Tube is) feeds the evaporator.

Report back your findings

[kb99]

The compressor is running and the condenser is plumbed correctly. Do not know if there is an orifice in the condenser line, what will it look like and which line should it be in? Oops, just reread your post about location of orifice tube, does it come with the new condenser or is it a seperate part?

[brcidd]

depends on manufacturer, the installer is responsible for insuring it has one.

[kb99]

thanks for the help, is there any more info that would help with the install of the orifice tube? is it located at the condenser or at the evaporator?

[brcidd]

You said you changed condenser- we would not be questioning OT or OT location if it were near the evaporator!

Your OT is in (or should be in) condenser outlet- accessible through right turn signal lens hole- without removing the grille. Look for the end of it inside the outlet pipe (bottom one) after you disconnect the connection. It should be a black OT- black means condenser outlet mounted.

[j cAT]

Originally Posted by kb99

Replaced the condenser and manifold on a 1997 chevy silverado and drew a vacuum on the system, when adding freon to the system the first can pushed the pressure up to 70 PSI on the low side and it has stayed there. Any help?

If the system has air[moisture] in the system this will create high suction pressures. the oil inside the system on extended exposure to air absorbs mositure. vacuum time is greatly increased to boil this off. when you vacuumed the system how long did the vac hold when the pump was shut off ? what are the high side pressures ?

[kb99]

vac held for at least thirty minutes before attempting to charge system, run vac pump for about one to one and a half hours. High side was about 150 -170 psi.

[j cAT]

Originally Posted by kb99

vac held for at least thirty minutes before attempting to charge system, run vac pump for about one to one and a half hours. High side was about 150 -170 psi.

if the oriface tube is clean and the low side is high and the high side is low your compressor may be weak .

[brcidd]

Those compressors are known for internal reed failures, does compressor turn very, very easily? if so it probably has a reed(s) failure. and will need to be replaced- most obvious evidence is stainless steel residue in orifice tube screen.

[chrschrsz]

My 1997 Silverado does not blow any air out of it, I am familiar with the charging Freon process, but I am not familiar about where to start looking about the blower not working or where to look. Please help me, thank you and have a good day.

[brcidd]

If blower motor is inop- check connector plug- it is under dash passenger side- if connection is okay- verify voltage- if voltage okay- replace blower motor after bench check.

[Tech II]

I agree....if motor doesn't run, turn the blower on and give the housing a love tap with a hammer.....if it runs, need a motor.....if it doesn't, attach a test light to the harness......as you go from low to high, the test light should get progressively brighter.....if it does, need a motor...

If it doesn't, check power and ground separately at the harness....if no power, check the fuse....if fuse ok, check for power into the resistor block.....if you have power in, and none out, bad resistor block.....if no power in and fuse ok, bad control head....

If you have power on the power leg of the harness, then you have to check the ground side of the harness....

[chrschrsz]

Thank you very much for the information, could you please let me know where the resistor block is, thanks again.

[brcidd]

It is on the other end of the purple wire that feeds the blower motor- trace it back to resistor pack.